This invention relates to a pattern transfer method and a silver halide photographic plate to be used for said method.
Heretofore, by use of a photographic plate comprising a silver halide emulsion formed on a glass support, it has been practiced to form an original picture pattern thereon and copy a pattern by transfer of said original picture pattern by contact exposure of this photographic plate onto another photographic plate, or to obtain a photoresist pattern by transfer of said original picture pattern by contact exposure onto a substrate having a photoresist layer.
Whereas, in the prior art techniques, contact during transfer of the original picture pattern by contact exposure is not necessarily sufficient, because of generation of contact irregularity, generation of Newton ring, etc., whereby good image quality may not be obtained even when transferred. Also, it is practiced to effect contact between the photographic plate and the pattern transfer medium by aspiration by means of an aspirating evacuation means, but this aspirating evacuation is time consuming such that bulk productivity is not improved.
In the case when a photoresist layer is formed on a substrate having a coated film of aluminum, etc., thereon and an original picture pattern on a photographic plate is desired to be transferred thereonto, it has been employed in various fields of electronic materials, such as in production of IC circuits, to transfer a circuit pattern by printing on the photoresist, followed by developing and etching working thereof to form a desired circuit. However, due to the above problem, resolving power cannot be enhanced, whereby a circuit with high reliability cannot be obtained. Also, when an aspirating evacuation means is used in order to increase contact for obtaining a good circuit, this will take a long time and thus productivity cannot be enhanced. Also, for the original picture pattern, it is frequently practiced to produce a duplicate pattern (working pattern) by transfer of the master pattern of said original picture to another photographic plate, but similar problems occur in this case.
In the photographic plate of the prior art as described above, there is the problem that no sufficient contact can be made during contact transfer of the original picture pattern.